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		<center><h3>Creation of a Pendulum (3/8)</h3></center>
		<div id="orangeText">Description</div>

		<p>Now that we managed to submit a particle to Gravity, let's try to fix a particle in space using a <strong>constraint</strong>. Several Sofa components implement the concept of constraints.</p> 

		<div id="orangeText">Key points</div>

		<p>To fix a particle to its position, we use a filter based constraint called <strong>FixedConstraint</strong>. It sets to zero the velocities and acceleration of a set of particles. </p>

		<p><div id="tutorialAction">Type "FixedConstraint" into the <strong>Filter</strong> textbox in the Modeler. Drag and drop the <strong>FixedConstraint</strong> component over the <strong>FirstObject</strong>  node. Then press the <strong>Run in SOFA</strong> button.</div></p>

		<p>As debug information, we use pink squares to indicate the fixed particles. </p>

		<div id="orangeText">Results</div>

		<p><div id="tutorialAction"> Press <strong>Animate</strong>.</div></p>

		<p>The particle doesn't fall anymore. </p>

		<p><div id="tutorialAction"> Double click the <strong>FixedConstraint</strong> node in the Modeler's scene graph. Click on the <strong>Property 2/2</strong> tab. </div></p>
                
		<p>Here you can specify several indices corresponding to the particles to be constrained. </p>

		<p><div id="tutorialAction">Press <strong>OK</strong> to return to the Modeler.</div></p>
        
        <p>SOFA implements many different types of constraints. As with Gravity, there are examples in the Modeler that you can take a look at. </p>

	
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